The 13-lipoxygenase MSD2 and the ω-3 fatty acid desaturase MSD3 impact Spodoptera frugiperda resistance in Sorghum

• Published in: Planta Vol. 252; no. 4; p. 62
• Main Authors: Block, Anna K., Xin, Zhanguo, Christensen, Shawn A.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01-10-2020
• Subjects: Agriculture; Animals; Biomedical and Life Sciences; Ecology; Fatty Acid Desaturases - metabolism; Forestry; Herbivory; Life Sciences; Lipoxygenase - genetics; Lipoxygenase - metabolism; Mutation; Oxylipins - metabolism; Plant Defense Against Herbivory - genetics; Plant Sciences; Short Communication; Sorghum - enzymology; Sorghum - genetics; Sorghum - parasitology; Spodoptera - physiology; Plant; Insect; Defense; Jasmonic acid; Oxylipin; Stress
• ISSN: 0032-0935; 1432-2048
• DOI: 10.1007/s00425-020-03475-2

Main conclusion
Linolenic acid produced by the ω-3 fatty acid desaturase MSD3 in sorghum is used for insect-induced jasmonic acid production and is important for resistance against
Spodoptera frugiperda
.
Jasmonic acid (JA) is a phytohormone that regulates both plant development and stress responses. In sorghum (
Sorghum bicolor
), the ω-3 fatty acid desaturase Multiseeded3 (MSD3) and the 13-lipoxygenase Multiseeded2 (MSD2) are important for producing JA to regulate panicle development and spikelet fertility, but their function in plant defense remains unknown. In this study, we examined whether these genes are important for the production of JA in response to herbivory by the insect pest
Spodoptera frugiperda
. Compared to wild-type controls, the
msd3
mutant accumulated less JA in leaves of both infested and uninfested plants
,
revealing that MSD3 is involved in stress-induced JA production. In contrast, herbivore-induced JA production in the
msd2
mutant was indistinguishable from wild type, indicating that MSD2 does not function in herbivore-induced JA production. An increase of
S. frugiperda
growth was observed on both the
msd3
and
msd2
mutants, hinting at roles for both JA and additional oxylipins in sorghum’s defense responses.